In this April 18, 2011 file photo, the Yahoo logo is displayed outside of the offices in Santa Clara, Calif. (AP Photo/Paul Sakuma, File)

(Newser)
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As Marissa Mayer puts it, "Tumblr. + Yahoo! = !!" As Tumblr CEO David Karp puts it, "F--- yeah." The two companies this morning announced that a definitive agreement has been reached and that Yahoo will indeed acquire Tumblr for $1.1 billion, a transaction that Mayer expects will close in the latter half of 2013. In her own Tumblr post announcing the deal (via animated gif), she writes, "We promise not to screw it up." More on that theme:

Mayer insists Yahoo won't muck up Tumblr: "We will operate Tumblr independently. David Karp will remain CEO. The product roadmap, their team, their wit, and irreverence will all remain the same ... Yahoo! will help Tumblr get even better, faster."

But writing for Forbes, Peter Cohan sees the acquisition as a losing one: That's because it "fails four tests of a successful" one, he writes. In brief: Yahoo is paying too much; integrating Tumblr may be tough, with potential friction arising if Yahoo wants Karp "to push display advertising onto Tumblr’s customers"; Tumblr's industry ("interactive advertising") is not more attractive than Yahoo's (display advertising); and the combined companies won't be better off vis a vis competing with Google.

Writing for CNET, Dan Farber echoes the integration concerns: Sure, you can attach Tumblr to Yahoo in a way that keeps it separate (think Google and YouTube), but that "won't do much to enhance the Yahoo brand. It might work to keep Tumblr's loyal users, already suspicious about the new overlord, from bolting. But Yahoo still needs to find a way bring them more deeply into the fold."

At Time, Harry McCracken points to Google-YouTube, too: Mayer hails from Google, which means she "has behind-the-scenes knowledge" of that acquisition. Let's hope she remembers what she learned, because that deal "remains shining proof that a big Web company can buy a cool, small Web company without messing it up."